When developing medical or sterilization devices, engineers often prioritize safety measures against harmful exposure from medical light sources. This is considered a high-compliance issue during product development.
However, options for UV-blocking encapsulation materials are limited. The material must allow high visible light transmission without interfering with therapeutic laser performance, while also filtering harmful UV radiation. It must also be durable and resistant to high temperatures and radiation — for example, CO₂ lasers (10,600 nm) and Er:YAG lasers (2940 nm) used in tumor ablation or scar removal typically operate at 100–300°C, vaporizing tissue through intense absorption by water molecules.
One of the best commercially available materials is the cerium-doped quartz tube, such as those offered by totalquartzworks.com under their UV Block Quartz Tube series. These tubes utilize cerium ions (Ce³⁺/Ce⁴⁺) to strongly absorb harmful UV bands.
1. UV Wavelengths Filtered
UV Type | Wavelength Range | Associated Risk | Filtration Effect |
---|---|---|---|
UVC | 100–280 nm | Causes severe skin and eye damage; DNA disruption | High absorption, especially at 200–280 nm; nearly complete blockage |
UVB | 280–315 nm | Leads to sunburn and increases risk of skin cancer | Partial absorption; strong effect from 280–300 nm, weaker above 300 nm |
UVA | 315–400 nm | Penetrates deep, causing skin aging and pigmentation | Weak absorption; often supplemented with coatings such as TiO₂ |
2. Key Applications
Medical and sterilization devices:
Used as observation windows in germicidal lamps (e.g., 254 nm), allowing visible light transmission while blocking UVC to protect users.
Semiconductor lithography:
Filters shortwave UV from excimer or mercury lamps (e.g., 193 nm, 248 nm) to reduce stray light damage.
Aerospace and nuclear industries:
Shields harmful UV radiation in high-radiation environments while maintaining optical transparency.
3. Advantages and Limitations
Advantages:
- High visible light transmittance (400–700 nm)
- Excellent resistance to heat and radiation
- Longer lifespan compared to organic UV filters like PMMA
Limitations:
- Weak UVA blocking; often requires co-doping or surface coatings
- Filtration performance depends on doping uniformity, requiring precise manufacturing
4. Comparison with Other UV Filter Materials
Matériau | Effective Filtering Range | Limitations |
---|---|---|
Cerium-doped quartz tube | 100–300 nm | Weak for UVA |
Standard quartz glass | Below 200 nm | Ineffective for UVC/UVB |
Borosilicate glass | Below 300 nm | Low absorption, needs high thickness |
Organic UV filters | Tunable by formula | Age rapidly, low temperature resistance |
Summary
Cerium-doped quartz tubes are ideal for blocking shortwave ultraviolet radiation (UVC and part of UVB), particularly in high-temperature and high-radiation environments. For broader protection, such as full-range UV shielding in personal care or consumer applications, combining with other materials is recommended.